The invention relates generally to power-driven conveyors and more particularly to transfer systems providing a surface over which articles are transferred between mutually perpendicular conveyor belts.
Many conveying applications require that articles conveyed on a first conveyor belt be transferred off the end of the belt onto a second conveyor belt transverse to the first conveyor belt. Dead plates positioned in the gap between the end of the first conveyor belt and the side of the second conveyor belt provide a slide surface over which articles are pushed toward the second conveyor belt. In pasteurizer discharge applications, for example, the first conveyor belt is typically a wide raised-rib belt conveying bottles or cans through a pasteurizer. The bottles or cans sit atop spaced apart ribs forming the belt's conveying surface. One or more plates having a series of parallel fingers are arranged at the discharge end of the raised-rib belt with the fingers extending between the ribs to strip bottles or cans from belt. Because of the space required at the discharge end of the raised-rib belt to accommodate the belt's path around its sprockets, the discharge belt cannot be positioned too close to the raised-rib belt. So the length of the slide surface of the finger plate between the two belts is typically greater than the footprint of the bottles or cans. Trailing bottles or cans push leading bottles or cans across the fingers and onto a discharge conveyor belt. But straggling bottles or cans in a batch can be stranded on the finger plate. Manual intervention is then necessary to push the stranded stragglers onto the discharge conveyor.
One solution to the problem with stranded bottles or cans is addressed in U.S. Pat. No. 7,314,130 to de Geus et al., which describes a finger plate with a recessed rear portion that supports an intermediate conveyor belt between the fingers and the discharge belt. The intermediate belt advances parallel to the discharge belt. A guide rail at a downstream end of the intermediate belt guides the bottles or cans onto the discharge belt. The edge of the intermediate belt closer to the raised-rib belt has a thin cantilevered edge that allows it to extend over the raised-rib sprockets without interference into close proximity to the rear of the fingers. In this way, the distance along the finger plate between the release point of the bottles or cans from the raised-rib belt onto the fingers and the edge of the intermediate belt is less than the footprint of the bottles or cans. Consequently, even the last bottles or cans are drawn onto the intermediate conveyor belt and directed to the discharge belt without being stranded. But this system requires that the guide rails be set correctly to guarantee that stragglers clear. And the intermediate belt is subject to lifting when broken glass pieces from bottles wedge themselves under the transfer edge. Furthermore, space limitations, especially in existing pasteurizer layouts, often do not allow room for an intermediate belt to be installed.